Several studies have examined accumulation of contaminants in vertebrates in the Hackensack Meadowlands. Galluzzi (1981) studied mercury concentrations in reptiles, mammals and birds collected from different sites in the Meadowlands. Despite the presence of a geographic gradient of mercury contamination in sediments within the Meadowlands, no geographic pattern was observed among biota in that study. Santoro and Koepp (1986) found a discrepancy between the concentration of mercury in sediments from the heavily contaminated Berry’s Creek and concentrations in fish species collected there. The lack of correlation between sediment and tissue mercury levels in these studies could be related to the bioavailability of these contaminants, the mobility of many animal species, or to dietary and other differences in local populations within the Meadowlands.
In a study comparing heavy metal concentrations in sediments, water, and northern diamondback terrapin stomach contents and liver tissue between Cape May and the Hackensack Meadowlands, C. McIntyre (unpublished report) found that while the Meadowlands were more polluted, tissue from Cape May terrapins had higher concentrations of copper, zinc, and cadmium. There were dietary differences between the two areas that may explain the counterintuitive differences in metals accumulation in terrapins. Albers et al. (1986) compared PCB concentration in livers of snapping turtles from the Hackensack Meadowlands (contaminated sites) with that of turtles in Maryland (less contaminated) but did not find a difference. Turtle trapping produced no catch in Mill Creek and Berry's Creek, the most contaminated sites sampled in the Meadowlands, although snapping turtles were successfully captured at several other sites (Albers et al. 1986).
Kraus (1989) compared the accumulation of heavy metals in different tissues of embryonic and nestling tree swallows as well as midges (Chironomidae), their primary food source in the Meadowlands. Swallow eggshells contained higher concentrations of cadmium, chromium, copper, lead, and nickel than embryonic tissues. There was differential accumulation of heavy metals among tissue types (brain, liver, muscle, feather) in nestling swallows. The study demonstrated that heavy metals can move from sediments to tree swallows via their prey source, midges.
Several studies have been conducted on fish and crustaceans in Berry’s Creek, a site heavily contaminated with mercury. In a study along a distance gradient from the mercury source at the headwaters of Berry’s Creek, Santoro and Koepp (1986) found that mercury concentrations in finfish and crustaceans were elevated but were several orders of magnitude lower than mercury concentrations in local sediments. Furthermore, several species exhibited higher mercury concentrations “downstream” from the most heavily contaminated areas. Mummichog, blue crab, and fiddler crab were the only animals sampled that exhibited a positive correlation between average mercury concentrations in tissue and distance from mercury point sources on Berry's Creek. Mercury concentrations in mummichogs ranged from 0.29 gg-1 (micrograms per gram [wet weight, fide E. Konsevick, NJMC]) at Berry’s Creek to 0.11 g▪g-1 at both Overpeck and Sawmill Creek. The highest individual concentration of mercury (0.61 g▪g-1) was found in yellow perch and the lowest (0.10 gg-1) in bluegill, both at Overpeck Creek. A mean mercury concentration of 0.44 gg-1 was detected in American eel samples from Berry’s Creek (the only site in which this species was sampled). This study involved several hundred samples from 15 species of fishes and 5 crustaceans. Santoro and Koepp (1986) stated, “Only 2% of Berry’s Creek data (0% for other biozones) resulted in individual values in excess of the existing Food and Drug Administration > 1.0 microgram per gram guideline…However, approximately 31% of all analyses were in excess of the prior 0.5 microgram per gram guideline as follows: Berry’s (9%), Sawmill (8%), and Overpeck (14%).” Species exceeding the lower guideline included mummichog, white perch, blueback herring, sunfishes, American eel, yellow perch, European carp, and blue crab.
Weis et al. (1986) studied the effects of different environmental factors on the release of mercury from Berry’s Creek sediments and its uptake by mummichogs. They found that decreased dissolved oxygen levels (similar to summer conditions) enhanced mercury uptake but stirring (to simulate dredging) did not. Furthermore, mercury concentrations in sediment did not relate to the uptake by fish.
Toxicological studies of the physiological, behavioral and developmental effects of chemical pollutants on estuarine organisms are extensive and a review of that literature is beyond the scope of this paper. However, several studies and reviews are immediately relevant to this discussion. In a review of the literature on whether exposure to toxicants may bring about physiological acclimation or genetic tolerance in aquatic organisms, Weis and Weis (1989) provide examples of these phenomena. Furthermore, they describe a case in which acclimation to locally present forms of mercury (methyl mercury specifically) entails costs as well as benefits. Mummichogs in Piles Creek, a nearby polluted tributary of the Arthur Kill, are more tolerant to methyl mercury than individuals from more pristine estuaries. However, they exhibit signs of poor health that include decreased growth and increased mortality in adult stages. Furthermore, mummichogs in this polluted environment show signs that they are allocating larger amounts of energy to reproduction and reproducing at an earlier age than those in less contaminated locations. Weis and Weis mention that fiddler crabs and grass shrimp from Piles Creek also exhibit enhanced tolerance to methyl mercury. Weis et al. (2001) review the literature on behavioral effects of environmental toxicants and offer an illustration of the ecological consequences via a case study of mummichogs and their prey, grass shrimp, in Piles Creek as compared with a sample from a cleaner estuary. Mummichogs from the polluted estuary were slower to capture prey and escape predators. Mummichogs from the polluted site had a higher amount of detritus in their diet, reduced growth and reduced longevity as compared to the largely crustacean diet in less contaminated areas. The consequence was that grass shrimp exhibited increased population density and larger size frequency in Piles Creek than those in cleaner locations. This shows that pollutants may have indirect effects within ecological communities, which makes it difficult to predict the effects of pollutants in ecosystems. A study of the effects of petroleum hydrocarbons on phytoplankton communities in Piles Creek demonstrated a 3-fold increase in photosynthesis after exposure to phenanthrene (Kelly et al. 1999).
It is remarkable that a region as contaminated as the Meadowlands can support the fauna we have described above, and that reported contaminant levels are fairly low in water birds, snapping turtles, and other fish-eating animals. It is possible that: 1. The nekton-feeding water birds of the Meadowlands (e.g. pied-billed grebe, herons, bitterns, gulls, terns) are consuming mummichogs, fiddler crabs, or other prey that do not accumulate large amounts of contaminants (see Galluzzi 1981); 2. The studies conducted to date have missed the sites, prey species, predator species, population classes, or tissues where contamination is having a deleterious effect on top predator species; or 3. Common reed and other plants are sequestering metals, or reduced conditions in the sediments are immobilizing metals, making them unavailable to higher levels of the food chains. Yet cautions concerning the potential effects of modest levels of mercury on health of fishes (Uryu et al. 2001) and water birds (Odom 1975) may be relevant to the Meadowlands. The studies of contaminants in tissues of Meadowlands vertebrates need to be reviewed and possibly replicated for confirmation of the low levels reported, and research needs to be done on the health effects of contaminants on animals. A study of contaminants in fishes and blue crab is underway (MERI, personal communication to EK 2002). Organic contaminants (e.g. dioxins, PCBs, PAHs) have not been studied as well as metals in the Meadowlands. Knowledge of contaminant effects on animals is important for planning management of habitats that may attract animals to, or discourage them from using, the more contaminated areas of the Meadowlands.
THE MEADOWLANDS AND WILDLIFE
What makes the Meadowlands such a magnet for wildlife? We think the following features of the Meadowlands contribute to their suitability for many animals: 1. A large complex of undeveloped habitats in a vast urban-industrial area; 2. Abundant surface waters with diverse hydrology (tidal and nontidal, fresh and brackish); 3. A variety of habitats ranging from open estuarine waters to dry fill and rock; 4. Extensive areas of marsh, wet meadow, and upland meadow habitat with minimal direct human intrusion; 5. Dense stands of common reed and other plant communities that have low visibility and low penetrability (i.e. they are hard to see into and move through, sensu Egler 1977:111), and provide concealment and shelter for animals nesting, roosting, or foraging within the reed stands or on other habitats surrounded by reed stands; 6. Abundance of certain foods (including common reed for muskrats; small rodents and small birds for raptors; terrestrial insects and spiders, as well as adult chironomid midges, for small birds; macrobenthic invertebrates for dabbling ducks, shorebirds, and small fishes; small fishes for piscivorous fishes, turtles, cormorants, herons, diving ducks, gulls, terns, etc.; and fiddler crabs for turtles, herons, etc.); 7. Reduced levels of hunting, trapping, and fishing activities that might potentially affect nontarget species and prey species as well as legally harvested species; and 8. Possibly reduced levels of predation, competition, and herbivory (e.g. deer grazing) providing ecological “refuge” for certain animals. We think these apparent advantages to life in the Meadowlands are “traded off” differently by different animal species with the detriments of the Meadowlands environment including: 1. Intensive replacement of “natural” habitats by altered or artificial habitats; 2. Loss of connectivity with other wetland and grassland habitat complexes; 3. Loss of sensitive species that may have served as food, symbionts, habitat structure, etc.; 4. Physical hazards of motor vehicles, aircraft, buildings, radio towers, and construction equipment; 5. High anthropogenic noise and light levels; 6. Urban-type water, soil, and air quality; 7. Contamination by metals and other toxic substances; and 8. Competition or predation from a few common, urban-tolerant animals (e.g. Norway rat, raccoon). For example, salamanders may not survive in the Meadowlands because of the artificial upland soils, scarcity of forest habitat, and chemical contamination (as well as salinity), despite the abundance of wetlands. Many breeding bird species may thrive because of the abundant prey and lack of direct human disturbance, despite contamination of the environment. The species that thrive in the Meadowlands tend to be those species that are highly mobile and are presumably able to move between the Meadowlands and other habitat complexes via air and water corridors, while also being able to move among habitats within the Meadowlands and avoid hazards such as highways. Of course, in order to thrive in the Meadowlands, animals also have to be able to use the available plant communities, many of which are dominated by invasive plants.
IMPLICATIONS FOR CONSERVATION
The values of the Hackensack Meadowlands include: 1. Extensive wetlands and other green spaces within a large urban-industrial area; 2. Recreation opportunities; 3. Habitat functions for many rare birds and trust species of birds, fishes, and the diamondback terrapin, as well as for common species of native wetland biota; and 4. Ecological services (albeit studied poorly or not at all) including water quality amelioration in wetlands, storage of carbon, and flood modulation. The best case has been made for the biological values, especially for marsh and water birds and to a lesser extent fishes. These values will depend increasingly on protection of habitats and habitat complexes from degradation or destruction, maintenance or improvement of water and air quality, and remediation of landfills and hazardous contamination. Scarce habitat types (e.g. high salt marsh, low salinity tidal marsh, natural sand scrub, natural rocky ledges) especially need protection, as do specific habitat units critical to populations for reproduction, nursery, migratory “stopover,” and other special functions. Large blocks of habitat are important for certain species, e.g. breeding northern harrier and certain marsh and water birds. Many of the species for which the Meadowlands are most important are relatively large and highly mobile animals such as marsh and water birds, raptors, and migratory fishes. These animals tend to use complexes of habitats within and outside the Meadowlands depending on season, weather, hydrology, disturbance, food availability, and other factors. This indicates that landscape and regional level patterns are important in addition to local habitat characteristics. We believe therefore that research, planning, and management of the Meadowlands need to consider both local and larger scale ecology in order to conserve the unusual wildlife of the region. Management and restoration of habitats and habitat complexes will play a role in this conservation. More than 400 hectares (1000 acres) of the Meadowlands are permanently protected (MERI, personal communication to EK 2002); however, several thousand acres of wetlands as well as important habitats on fill and natural uplands remain unprotected. The Hackensack Meadowlands are the largest remaining incompletely protected tidal wetland complex in the New York – New Jersey harbor estuary and one of the largest remaining contiguous blocks of open space in the New York metropolitan area (Day et al. 1999).
HABITAT MANAGEMENT AND RESTORATION
Targets for Restoration
We have described, within limits of available information, existing biological diversity of the Hackensack Meadowlands. The biodiversity of the future is inextricably related to the course of management and restoration activities in the Meadowlands. Ecological “restoration” can accomplish a variety of goals, among them restoration to a known prehistoric or historic condition, restoration of ecological processes, creation or enhancement of habitat to favor particular species of animals or plants, removal of non-native species or other organisms considered undesirable or detrimental, remediation of pollution or improvement in environmental quality (e.g. dissolved oxygen, nutrient levels, contaminant levels), or achievement of an aesthetic condition such as unobstructed views of water. Some goals of restoration may conflict; for example, providing extensive mudflats for shorebirds and having extensive robust emergent vegetation to ameliorate water quality are not necessarily compatible with each other. Restoration “targets” should be clearly defined and realistic (i.e. achievable and sustainable). Restoration should re-establish ecological integrity and ecosystem processes as well as water quality and wildlife use (Berger 1992). Key organisms and environmental factors should be monitored before and after restoration, and the results of monitoring made available to the public promptly, so that new projects can benefit from prior experiences.
The concept of restoring Meadowlands marshes to salt marsh has been criticised because salt marshes were not historically dominant in this landscape (Day et al. 1999). Salinities may not be high enough in many portions of the Meadowlands to allow plants such as saltmarsh cordgrass to compete with common reed in the long term, although large patches of saltmarsh cordgrass have persisted on the site of the first major mitigation project in the Meadowlands (the Hartz Mountain project) after 15 years. (Cordgrass on this mitigation site, however, is reported not thriving, short, and unproductive, and the soil low in organic matter [L. Windham, personal communication to EK and KM, 2001; also see Wander and Wander 1995].) Possibly sea level rise and the accompanying increase in salinity will favor salt marsh communities in the future. Restoration to Atlantic white cedar swamps, as proposed for part of the mitigation for the Meadowlands Mills development (USACOE et al. 2000), is unrealistic because the conditions required by this plant community (e.g. low fertility, acidic soils, no saline intrusions, low fire frequency) are probably unattainable (Kiviat 2000). NJMC twice attempted white cedar restoration unsuccessfully; plantings were killed by muskrats and a salinity intrusion (Waldman 1999).
One way to conceptualize effective restoration is to observe how ecosystems change. Restoration planning can grow from knowledge of, e.g., existing high quality habitat for marsh and water birds in the Meadowlands. Kearny Marsh West is a case in point. Accidentally blocked drainage turned a brackish tidal marsh into an impoundment and raised the water level. This caused a dense stand of common reed to break into fragments interspersed with shallow open water, and created some of the best habitat for breeding marsh and water birds in the Meadowlands. Use of impoundment (permanent, temporary, or controllable) to manage extensive dense reed stands and increase interspersion should be considered at certain sites. Restoration and management in the Meadowlands, of course, must be designed to reduce (or at least not aggravate) flooding of developed areas, production of nuisance and vector mosquito species and other nuisance biota, and fire hazard. Management of reed marshes as habitat should address a broad taxonomic spectrum. Because of the limits of knowledge of reed interactions with many taxa, however, our discussion of habitat focuses on birds and fishes.
Impoundment of Tidal Marshes
Impoundment can produce a stable (or controllable) water level and, if correctly designed, vegetation favorable for breeding of marsh and water birds (see above). Impoundment, however, reduces or eliminates the ability of the marsh to ameliorate estuarine water quality, export plant detritus to the estuary, and act as spawning or nursery habitat for migratory fishes. Impoundments are also vulnerable to undesirable invasions in the water (e.g. purple loosestrife, water-chestnut [Trapa natans], European carp) and on the dikes (tree-of-heaven, princess tree). The structure of reed stands in impoundments varies depending on water depth and probably other factors. At Kearny Marsh West, where water is deep, reed stands are fragmented, interspersed with open water, and declining. At Kingsland Impoundment, reed stands are interspersed with open water, appear to be less fragmented than at Kearny West, and may be more stable. At the Carlstadt-Moonachie Marshes, where a berm has kept tidal flow out of large areas, and standing water is shallow, of shorter duration, and restricted in extent, reed stands are more continuous, hyperdominant, and presumably stable.
Managing Water Levels
The fragmentation of common reed stands in Kearny Marsh West appears to be progressing beyond an optimal state for marsh and water bird habitat. The combination of permanent high water, poor water quality, muskrat and European carp grazing on reed rhizomes, and flotage of peat where reed has died may result in conversion of large areas of marsh from interspersed reed and open water (i.e. a deep reed marsh) to a floating purple loosestrife and marsh-fleabane marsh (EK, personal observation, 2000). Although this mixed loosestrife community may provide resources to butterflies, meadow vole, and several marsh and marsh-edge bird species, this habitat may not be good for animals of deep marsh such as common moorhen, American coot, and least bittern. It may be necessary to lower the water level permanently or seasonally to stabilize the reed stands. Additional action may be needed to break up or sink some of the floating peat mats. Detailed study of water quality, vegetation dynamics, and habitat use by birds is needed. A similar problem does not seem to exist in the Kingsland Impoundment, which is also good deep reed marsh habitat for breeding marsh and water birds. A careful comparison of these two marshes may be in order.
Drawdown of Impoundments
Seasonal drawdown (July through October) to expose mudflats in the Kingsland Impoundment would attract southward-migrating shorebirds (Kane and Githens 1997). This would provide a habitat for foraging and loafing at times of higher tides when these activities are limited in the nearby tidal marshes. Drawdowns also contribute to use by birdwatchers, important because the Meadowlands are an important birdwatching area (R. Kane, personal communication to EK and KM, 2001). Seasonal drawdowns should be considered for other impoundments as well. The potential during and following drawdowns for invasion by purple loosestrife or for excessive proliferation of common reed, or of volatilization of organic contaminants such as PCBs, needs consideration.
Removal of Tide Barriers
Tidal flow may be restored to impounded or semi-impounded areas by removal or modification of tide gates, dikes, berms, or other water control structures. This action has good potential to restore saltmarsh cordgrass stands and diversify common reed stands in some places (Day et al. 1999). Tidal barriers at Sawmill Creek WMA were breached by a storm in 1950 allowing increased tidal flooding. A decrease in common reed and an increase in mudflats and low salt marsh resulted (Day et al. 1999). It has been suggested (B. Sheehan, personal communication to EK, 2000) that the flood control berm on the Hackensack River side of the Carlstadt-Moonachie site (including the Empire Tract) could be relocated to the “landward” or developed side of the marsh, maintaining flood protection for developed areas but allowing tidal flooding of the marsh. Depending on topography, it might be necessary to create or deepen creeks and pools within the common reed matrix in the marsh to open substantial areas to tidal flow. Substrate elevation and microtopography will influence species and abundances of fishes using the marsh. Restoration of tidal flow to marshes may allow stands of reed and other marsh plants to ameliorate the quality of estuarine waters.
Reed removal by means of repeated herbicide (glyphosate) applications alone or in combination with other techniques, recontouring of the soils, and planting of preferred species such as cordgrasses has been practiced in several mitigation projects in the Meadowlands. These projects are located primarily at Mill Creek (the first major mitigation project in the Meadowlands as well as a new mitigation project), the Meadowlands Mitigation Bank (TransCo property on eastern portion of the Carlstadt-Moonachie site), Skeetkill Marsh, and Harrier Meadow. Additional sites have been identified as potential mitigation sites (including Oritani Marsh, Riverbend Marsh, and Kearny Marsh) according to an undated NJMC map labelled “Current & Potential HMDC Wetland Mitigation Sites”; however, this map does not imply that reed removal is anticipated at all those sites. The stated goals of reed removal projects in the Meadowlands are to remove common reed, lower the substrate and increase tidal flooding, establish a native plant community such as saltmarsh cordgrass, improve the ability of the marshes to ameliorate water quality, increase export of plant detritus to the estuary, make the marsh more available to estuarine nekton (fishes, crabs, etc.), create foraging habitat for shorebirds, waterfowl, and long-legged wading birds, and create opportunities for environmental education and passive recreation (K. Scarlatelli and others, “Wetland Mitigation Banking in the Hackensack Meadowlands District” workshop at NJMC, 20 October 1998). These responses, however, are in some cases not proven to result from reed removal, may be in conflict with each other, and in other cases may occur in the short term but may not be sustainable. In the 1998 workshop, Scarlatelli stated that more than 700 acres of mitigation were already completed or in progress, and 530 acres were planned, for a total of more than 497 hectares (more than 1,230 acres). Current and planned NJMC wetland “enhancement” sites encompass more than 688 hectares (1,700 acres) (HMDC 1999); this would involve 20% of the total remaining wetland area of the Meadowlands). NJMC maintains 11 mitigation sites (J. Quinn, personal communication to EK, 2001). The Environmental Improvement Program of NJMC calls for 3,400 acres (1,376 hectares) of wetland “restoration” overall (Scarlatelli 1997). The majority of these acres may be subject to reed removal. NJMC, however, has decided not to perform any new mitigation or mitigation banking, although these activities may still occur on private lands (Robert Ceberio, NJMC, personal communication to EK, 2002). A wetland enhancement project is planned for a 15 ha (38 acre) site near the Secaucus High School (L. Houston, U.S. Army Corps of Engineers, statement at U.S. Fish and Wildlife Service workshop, 31 October 2001; Anonymous, no date b). The New Jersey Transit Authority is planning a 20 ha (50 acre) reed removal project in the Penhorn Creek area near the Turnpike and Route 495 (A. Fekete, statement at USFWS workshop, 31 October 2001).
Apart from the expense of reed removal, many questions remain unanswered about nontarget impacts and sustainability. These include effects of herbicides on nontarget organisms including rare plants, habitat impacts on rare animals and plants, loss of the water quality amelioration (see Findlay et al. 2002), soil stabilization, and other key functions and values of reed marsh, remobilization of contaminants via soil disturbance and replacement of reed by saltmarsh cordgrass (see Burke et al. 2000), release of carbon dioxide and methane, and short term loading of estuarine waters with nutrients, suspended sediment, dissolved organic matter, and oxygen demand. The trading of filling and development of wetlands for enhancement of wetland via e.g. reed removal represents a net loss of wetlands (Berger 1992), although it has been argued that this process may represent a net increase in wetland function (Kraus 1988).
Findings from recent research on common reed ecology require re-examination of the scientific basis for this restoration method and these goals. There may be less intensive methods that can accomplish the stated NJMC goals as well as or better than reed removal, while maintaining many of the important functions and values of reed stands (e.g. water quality amelioration, sediment stabilization). NJMC approaches to wetland mitigation appear to be moving away from strict reed removal to a mixture of different types of treatment. Planning for any form of restoration, of course, should be preceded by thorough biological surveys and habitat assessments (R. Kane, personal communication to EK and KM, 2001). The study conducted by Berger Group (2001) of the prospective mitigation site at Oritani Marsh is a step in this direction.. Some of the sampling methodologies (e.g. mammals, birds) were not necessarily adequate to fully characterize these communities and detect any rare species. For example, only 200 Sherman trap-nights and 200(?) pitfall trap-nights were invested in the small mammal survey, and there apparently was no rare plant survey.
Replacement of reed by saltmarsh cordgrass in the Hartz Mountain mitigation project at Mill Creek resulted in establishment of a stenotopic (narrow habitat niche) bird, seaside sparrow. Bontje (1988) reported seaside sparrows on the mitigation area and none on an adjoining, reed-dominated, reference site. We do not know if seaside sparrows bred successfully or persisted at the Hartz Mountain site. Krivenko (2001) analyzed relative abundance data from bird surveys at the Mill Creek mitigation site before and after mitigation. Use of the site by waterfowl, waders, shorebirds, and gulls and terns increased, whereas use by raptors and “land birds” (i.e. passeriform birds) decreased. Mudflats, open water, and sparsely vegetated islands apparently attracted water birds post-mitigation, whereas the removal of reed stands eliminated habitat for land birds. It will be important to see if the attraction of water birds to recently-created habitats is associated with a short-term “flush” of production of invertebrate or other food, or if it is a long-lasting habitat effect. Reed replacement and partial reed replacement projects are described by e.g. Bontje (1988) and Doss (2000).
Altering Soil and Vegetation in Existing Reed Stands
Some reed stands may appropriately be managed by diversifying topography, hydrology, and vegetation without large-scale removal of reed. Possible techniques include creation of shallow ponds, thinning by means of repeated summer mowing, and planting woody species. Sparse shrubs or trees in certain Meadowlands reed stands provide important nest sites for birds (R. Kane, personal communication to EK, 2000). Wet soils, and at some sites salinity intrusion, may be unfavorable for many woody species; however, common elderberry, groundsel-tree, marsh-elder, sweet gum, and others may survive under Meadowlands conditions. These and other reed management techniques have been used in Europe and elsewhere to alter reed stands for specific goals including enhancement and maintenance of habitat for rare plants, native plant communities, rare birds, rare insects, and other species. European reed management has been discussed by Burgess et al. (1995), Hawke and José (1996), and others. Some American counterparts have been described by E. Ward (1942), P. Ward (1968), and Tesauro (2001). It may be possible to enhance fish use of reed marshes by restoring or creating the various-sized creeks and pools that are generally believed to provide access to the marsh for fish and other nekton.
Removal of Fill
There are many areas of wetland fill in the Meadowlands that are not in active, formal use. An example is the peninsula of fill projecting eastward into the Carlstadt-Moonachie marshes from the end of JoMike Court in Carlstadt (USACOE 2000), and the large area of fill west and northwest of the Meadowlands Convention Center in Secaucus (EK, personal observation, 2002). In some areas, it may be feasible to remove fill and restore wetland soils, hydrology, and vegetation. This might be more costly than reed replacement, but has the advantage of not compromising existing wetland functions and values. Of course, the ecological tradeoff of extant functions of the ecosystems developed on fill (e.g. upland meadow and shrubland) compared to those of restored wetland would need to be evaluated. It may be timely to perform an inventory of such “idle” fill areas as potential restoration sites. Fill removal has been proposed for the northern portions of Oritani Marsh (Berger Group 2001).
Artificial or Emplaced Natural Structures for Wildlife
Creating structures for wildlife nesting and other activities generally has few ecological side-effects and can be useful alone or in combination with other habitat manipulation procedures. Appropriate structures might include: 1. Nesting boxes for eastern bluebird, tree swallow, purple martin, wood duck, eastern screech-owl, and American kestrel; 2. Nesting platforms for osprey, barn-owl, and waterfowl; 3. “Boxes” for roosting bats and wintering butterflies; and 4. Basking logs or platforms for diamondback terrapin and other aquatic reptiles. Tree swallow nesting boxes are already successful at the Kingsland Impoundment (DeKorte Park) and other sites, and there are two butterfly boxes at DeKorte Park. Osprey platforms at DeKorte are not used (J. Quinn, personal communication to EK, 2001); the reasons are unclear. Structures need to be designed and installed properly, as well as maintained and monitored, and determinations need to be made as to whether structures (e.g. nesting sites) are limiting, or other factors (e.g. human activity, turbidity, contamination, vegetation) limit populations of the target species. Construction of artificial nest foundations on platforms helps attract nesting osprey (Paul Spitzer, personal communication to EK, 1973).
Pond and Marsh Construction
Construction of ponds or marshes atop capped landfills or on other fill areas could provide habitat for birds, aquatic invertebrates including dragonflies and damselflies, and other biota. If these surface waters were underlain by impervious clay or plastic liners, it might be feasible to maintain good “perched” water quality.
Large areas of the Meadowlands were occupied by forests until 100-200 years ago. Although re-creation of Atlantic white cedar swamps is likely impossible, there are other types of woody plant communities that could be created on both wetland and upland soils. One possibility is afforestation of closed landfills; experiments have been conducted by Stephen Handel (Center for Urban Restoration Ecology of Rutgers University and the Brooklyn Botanic Garden). Establishment of swamp scrub (carr) or swamp hardwood forest on high elevation wetland substrates should also be possible, provided areas are not subject to much salinity intrusion (tidal swamps occur naturally in oligohaline reaches of estuaries such as the Hudson River and the Mullica River, New Jersey). Woody species such as red maple, certain willows, gray birch, common elderberry, and alder that are native to the Meadowlands could be salvaged from legal filling of wetlands in nearby areas of New Jersey, and translocated to appropriate sites in the Meadowlands.
It should be feasible to create firebreaks around the margins of reed stands to reduce the likelihood of fires spreading from the reed stands to developed areas. Such firebreaks in wet areas could incorporate shallow open ponds or channels that would support submergent aquatic vegetation and provide foraging habitat for water birds, muskrat, and turtles. In dry areas, firebreaks could include ponds as well. Information is needed on effective size and shape of firebreaks bordering reed stands.
Livestock grazing is widely used in Europe and less so in North America (but see Tesauro 2001) to manage species composition of vegetation (including in some instances reduction of invasive plants) and improve habitat for various animal species. For example, there may be a role for horse or sheep grazing, which can inhibit or even kill common reed, in some areas of the Meadowlands. Contaminants could be a problem for livestock.
Beneficial Use of Invasive Plant Biomass
Potential beneficial use of invasive plant biomass should be considered. For example, biomass could be combined with organic matter from landfills or with “new” waste materials (e.g. lawn and horticultural wastes) for use in methane or ethanol production for generating electricity, or as an industrial feedstock. Common reed has been used for paper pulp in Romania and home heating fuel in Sweden; many other historic and current uses are known in North America and elsewhere. Tree-of-heaven is used for fuelwood, charcoal, lumber, furniture, and cellulose (Vietmeyer et al. 1980). Princess tree is potentially valuable for wood and medicine (Ellison 2001). Harvest of plant biomass could be a component in an integrated management program for common reed or tree-of-heaven.